OIL & GAS ACCUMULATION IN THE MIDDLE-LOWER ORDOVICIAN CARBONATE ROCKS OF THE WELL YQ3 IN YUQI BLOCK OF THE AKEKULE UPLIFT, TARIM BASIN

Yuqi block is an important oil gas exploration play of Tahe oilfield in Akekule uplift,Tarim Basin.The oil gas accumulation in the Middle-Lower Ordovician Yingshan Formation carbonate rocks of the Well YQ3 in Yuqi block are studied,main factors controlling hydrocarbon accumulation are analyzed by using the techniques of fluorescence slice and fluid inclusion under the guidance of the theories of oil gas accumulation.It is demonstrated that the carbonate rock reservoirs of the Well YQ3 are cave,fracture-hole and fracture type,there are a large number of Caves,corrosion holes,and medium-miniature fractures in the Well YQ3,but Cave filling is very serious;the seal conditions of Lower Carboniferous mudstone seal rocks are fair,but late Hercynia structural event is the most important influence element on petroleum preservation;there is existed four oil/gas charge in the Middle-Lower Ordovician Yingshan Formation carbonate rocks of the Well YQ3 in Yuqi block,and the most important charge periods are late Hercynian and Himalayan(Cenozoic);there were three main factors controlling hydrocarbon accumulations.